Deliver Valve Leak - Noted and Repaired - Filter and Soy? - PeachParts Mercedes-Benz Forum

stephenson · #1 06-18-2006, 04:57 PM

My 1991 350SDL sprung a number 5 cylinder delivery valve leak (at the IP) - weekend, of course was when I noticed it (backing out of garage downhill when my wife yelled - "oil leak!!!" (sort of like "squirrel!!!!" in the movie Christmas Vacation) the fuel had pooled big time in the bottom engine cover and ran out due to the angle) - should have payed attention to the indicator at the pump - last fill was down a couple of MPG! I had previously replaced copper gasket and o ring (about three years ago) on 1-3. Don't know if is related in any way, but I started using 20% soy about two months ago - frankly, the o rings looked pretty awful - not only were they distorted, there were multiple cracks.

So, out to the MB parts shelf to see what I had left from before - for a change, luck was going my way - I still had three of copper gaskets and o rings in sealed bags - even had a three line clip to replace the soon to be broke two line clip holding two to the lines together.

Oh yeah, I had the Hazet splined socket - the numbers I am hearing people paying for this in some of the threads is insane ... perhaps Phil can be talked into be a wholesaler for Hazet tools - I think mine was about $15 a few years ago. Not rocket science tool.

Disconnected IP line fittings on 4-6 (have to remove #4's retaining device in order to get retaining device off #5). Since I had gone this far I replaced seal and o ring on #4, too.

OK - lessons learned?

1. Replace ALL when you have a leak - they're cheap and you're gonna end up doing all of them at some interval anyway since the o rings are affected by heat and compression and fuel, etc. (maybe there is a diff with some biodiesel content?)

2. Pay attention to which way the "delivery valve carrier" (the machined, round holder for the delivery valve) - the slot goes down on my IP - there was a warning on the CD, but the diagram is not high res so would be easy to miss.

3. CD procedure calls for oiling the o ring prior to installation - don't forget as the likely allows it to more smoothly slide into position without stretching or crimping.

4. Torque - I wish I could say I did this by the book. My all purpose torque wrench is rather long and 1/2" drive - simply would not fit. I'm gonna get a lower reading, shorter, 3/8 drive wrench soon. I did three cycles of torque, light, medium (spark plug torque by feel), and then a bit tighter. Best guess only - I can always redo it .... :-)

5. Those darn clips! I had a few left over from when I removed my intake system and cleaned all the gunk out - are there stainless or regular steel versions available? Replacing all these in plastic each time any maintenance is done on an engine designed to last 300-400K miles is pretty silly.

6. The parts are cheap - next time I'm gonna buy two sets of everything - and be ready for the next, inopportune time it springs a leak - hmmm, it will likely be 1-3 since I replaced them last cycle - 4-6 this time ... say, 2012-2014?

Total time - an hour or so - mainly spent examining and marveling at all the bits!

BTW, I did notice my in line fuel filter was looking a bit dark - it had been clean since I replaced it about 18 months ago - also appeared the filter mesh had collapsed a bit - not just the thin mesh, but the framework plastic mesh. After replacing (had one of those, too!), I cut it apart to examine - about 20% blockage by small particles about the size and consistency of grains of sand - could this be the soy cutting away deposits from somewhere? Was this restriction enough to cause the filter mesh and support to collapse?

That's my Father's Day story!

sixto · #2 06-18-2006, 10:38 PM

2) This is made more confusing when some are groove up and some are groove down from previous work on the IP :/

Sixto

stephenson · #3 06-19-2006, 03:39 PM

Ahhh .... that makes it even more important to (1) pay attention when removing, and (2) have the repair CD for reference (if in doubt)!

BTW, I think the hammering, which was pretty loud to begin with is beginning to subside a bit after driving the bejeezus out of it today.

Thanks!